Question 151178
You are correct on part a
Part b asks when the temp will be 45 degrees
Given{{{T(t)=36+43e^(-.058t)}}}
{{{45=36+43e^(-.058t)}}}
{{{9 = 43e^(-.058t)}}}
{{{9/43 = e^(-.058t)}}}
{{{0.209 = e^(-.058t)}}}
{{{ln(0.209) = ln(e^(-.058t))}}}
{{{-1.565 = -.058t}}}
{{{1.565/0.058 = t}}}
{{{1.565/0.058 = 27}}}

about 27  minutes later.

Check your answer by plugging 27 into the original equation